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Finding the Fourth Proportional to 207.43, 311 and 85.57

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Solution

The fourth proportional to 207.43, 311 and 85.57 is: 128.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.43 : 311 = 85.57 : x
  2. Step 2: Convert to fraction form
    207.43/311 = 85.57/x
  3. Step 3: Cross multiply
    207.43x = 311 × 85.57
  4. Step 4: Simplify right side
    207.43x = 26,612.27
  5. Step 5: Solve for x
    x = 26,612.27/207.43
  6. Step 6: Final answer
    x = 128.30

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.